The tax deductions you and millions of other homeowners and buyers count on every April to help make ends meet may be dangerous to the nation's economic health.

They may inflate real estate prices, deprive industry of your investment dollars, and keep interest rates at record-high levels. We'd all be better off if the multi-billion dollar tax breaks for housing were cut down sharply.

That's the ominous, unsettling message contained in an 80-page Congressional Budget Office study released here last week. Although there is no immediate prospect that Congress will follow its recommendations, the report should be a political alarm bell in the night for anyone interested in real estate.

Don't assume that the current federal tax deductions for mortgage interest and property taxes are cast in concrete. They're not. Here's why:

For the first time ever, an influential arm of Congress--the Congressional Budget Office--has documented the full federal revenue costs associated with homeownership. The annual bill is huge--$39 billion this fiscal year, $86 billion by 1986--and it's an irresistible target for budget balancers on both sides of the political aisle.

The mortgage interest deductions Americans take off their federal tax payments will cost the Treasury more than $25 billion alone this year, according to the new study. The deductions most of the homeowners take for local property taxes will add on another $11 billion. Other breaks, such as the $125,000 tax-free exclusion on profits for home sellers 55 years and older, and tax-free "rollover" of capital gains on home sales, will add $3 billion more.

To put a clamp on the rapid projected growth of these tax costs--and help balance future federal budgets--the study offers a variety of tax code changes.

The first would slash the amount of mortgage interest you're allowed to deduct on your home in any one year.

The limit might be set at $5,000 or $10,000 for tax year 1982 or 1983, for example. The lower "cap" would touch the majority of recent home buyers in most markets across the country. All you'd need in monthly mortgage interest debt is $417 a month to hit that ceiling--roughly half the typical monthly payment on an average, newly purchased home in the United States this year. Any mortgage interest payments an owner made beyond the $5,000 cap would be non-deductible. Homeowners would get absolutely no tax advantage for the upper portion of their mortgage debt.

An alternative $10,000 limit suggested by the congressional study would touch fewer buyers in 1982 or 1983, but for those it did, the effects would be severe. The buyer of a house or condo with monthly interest payments over $850, for instance, would lose current deductions of $3,500 a year. The purchasers of a home carrying $1,500 a month in mortgage interest payments would lose nearly 40 percent of their current tax savings.

The Congressional Budget Office suggests other forms of cutbacks as well:

* The breaks for elderly home sellers could be eliminated or trimmed back (say to $50,000 instead of $125,000).

* Deductions for interest payments on second homes or vacation property could be eliminated or slashed.

* Local property taxes could be treated as "users fees" that benefit the homeowners directly--and thus made nondeductible under the federal tax code.

Homeowners could be given an across-the-board 25 percent tax credit on their mortgage payments every year--thereby opening tax benefits to the millions of families who own real estate but use the standard short form at income-tax time.

The new report may sound extreme, but don't underestimate its potential. The chairman of the House-Senate Joint Economic Committee, Rep. Henry Reuss (D-Wis), calls it "the most provocative and important study in its field Congress has ever seen."

He'd like to see some of its recommendations put into law--but he won't without holding hearings later this year or early in 1982.

Don't panic about tax deductions, but be aware of the beginnings of a serious movement on Capitol Hill--with tacit support from the Treasury Department and liberal Democrats in the House--to rein in real estate tax subsidies.

Kenneth R. Harney is executive editor of Housing & Development Reporter, published here by BNA, Inc.